Thanks for steering me to the rotor, it was the 1 thing I had not checked and was contemplating changing it as i had a spare which i got with the stator i bought a year ago… there is definitely no contact but it may have got damaged before i had the engine rebuilt several months ago, it does have some marks and scratches. Didn’t think such a simple thing could go wrong..

Avi I would recommend this is your next step as your symptoms appear exactly as mine were.

FYI I called my local Kart shop and they said ‘start replacing stuff’ thats what they would do..